Performance analysis of a multiple access protocol for voice and data support in broadband wireless LANs

Wireless local area networks (WLANs) are one of the most promising access technologies for the upcoming fourth-generation wireless communication systems. In the last few years, several research efforts have been devoted to investigate possible multiple access schemes capable of supporting real-time traffic as well as best-effort data transmissions. In particular, the use of suitable transmission schemes allows not only to achieve higher data-rates, but also to optimize the allocation of traffic in the radio resources depending on the service requirements. In this paper we propose a multiple access scheme for a WLAN supporting real-time (voice) and best-effort (data) services, which exploits the presence of a broadband multiuser wireless access scheme such as orthogonal frequency division multiplexing (OFDM). OFDM allows dividing the radio bandwidth into several sub-bands, thus permitting a flexible resource allocation strategy to be deployed, while satisfying quality of service (QoS) requirements. A high overall network capacity in terms of simultaneously active users is achieved by effectively exploiting the multiuser capabilities offered by OFDM, together with a good service differentiation. A suitable theoretical analysis for the considered protocol has been carried out by applying the equilibrium point analysis (EPA) method, and computer simulation results have been compared with analytical predictions.